Abstract

Setting up molecular models for the prediction of fluid phase behavior rests on an interdisciplinary basis of foundation, of which quantum mechanics and statistical mechanics are particularily relevant. Quantum mechanics provides molecular properties such as the geometry, multiple moments and polarizabilities or alternative formulations of the molecular charge distribution, which are required to calculate the energy of a molecular system. Statistical mechanics provides relationships between the molecular energy of the system and the macroscopic fluid phase behavior. Solving the statistical mechanical equations for the general case is possible by computer simulation. Due to the excessive amount of computer time required for the execution of such calculations this route is restricted to particular applications and to model development. For practical purposes solutions using simplifications tailored to the application under consideration are established. This paper reviews the field from an application oriented perspective.